Model Comparison
DiffusionGemma 26B-A4B vs GPT-5.5Which is better in 2026?
GPT-5.5 significantly outperforms across most benchmarks.
Verdict: DiffusionGemma 26B-A4B vs GPT-5.5 — which is better?
DiffusionGemma 26B-A4B (by Google) and GPT-5.5 (by OpenAI) are two of the AI models people compare most. Here is how they stack up on benchmarks, price and capabilities, and which one to pick in 2026.
DiffusionGemma 26B-A4B outperforms in 0 benchmarks, while GPT-5.5 is better at 3 benchmarks (GPQA, Humanity's Last Exam, MMMU-Pro). GPT-5.5 significantly outperforms across most benchmarks.
Choose DiffusionGemma 26B-A4B if…
- you want the most recent training data — it shipped Jun 2026
- you need open weights you can self-host or fine-tune
Choose GPT-5.5 if…
- you want the strongest raw capability — it leads on 3 of 3 shared benchmarks
Performance Benchmarks
Comparative analysis across standard metrics
DiffusionGemma 26B-A4B outperforms in 0 benchmarks, while GPT-5.5 is better at 3 benchmarks (GPQA, Humanity's Last Exam, MMMU-Pro).
GPT-5.5 significantly outperforms across most benchmarks.
Arena Performance
Human preference votes
Context Window
Maximum input and output token capacity
Only GPT-5.5 specifies input context (1,050,000 tokens). Only GPT-5.5 specifies output context (128,000 tokens).
Input Capabilities
Supported data types and modalities
Both DiffusionGemma 26B-A4B and GPT-5.5 support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
DiffusionGemma 26B-A4B
GPT-5.5
License
Usage and distribution terms
DiffusionGemma 26B-A4B is licensed under Apache 2.0, while GPT-5.5 uses a proprietary license.
License differences may affect how you can use these models in commercial or open-source projects.
Apache 2.0
Open weights
Proprietary
Closed source
Release Timeline
When each model was launched
DiffusionGemma 26B-A4B was released on 2026-06-10, while GPT-5.5 was released on 2026-04-23.
DiffusionGemma 26B-A4B is 2 months newer than GPT-5.5.
Jun 10, 2026
1 months ago
1mo newerApr 23, 2026
2 months ago
Knowledge Cutoff
When training data ends
DiffusionGemma 26B-A4B has a knowledge cutoff of 2025-01-01, while GPT-5.5 has a cutoff of 2025-12-01.
GPT-5.5 has more recent training data (up to 2025-12-01), making it potentially better informed about events through that date compared to DiffusionGemma 26B-A4B (2025-01-01).
Jan 2025
Dec 2025
11 mo newerOutputs Comparison
Key Takeaways
GPT-5.5
View detailsOpenAI
Detailed Comparison
Interactive Arena
Judge for yourself.
Run your own prompts against DiffusionGemma 26B-A4B and GPT-5.5 side-by-side, then vote on the output you prefer.
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FAQ
Common questions about DiffusionGemma 26B-A4B vs GPT-5.5.